Abstract: Process for purification of a liquid, said liquid being contaminated by gas, other liquids and/or solid materials, thereby a) degassing the contaminated liquid in a degassing device where at least a part of the gas and possible solid materials are removed from the liquid, b) mixing the liquid in a mixing and coagulation device by way of utilizing the energy in the liquid flowing into the mixing and coagulation device, thereby to achieve coagulation respectively flocculation of the contaminants in the liquid, and c) the coagulated or flocculated contaminants as well as gas and other liquids thereafter being separated from the liquid to be purified in a flotation and separation device.